1. Field of the Invention
The present invention relates to an optical pickup for recording information on an optical disk such as a DVD (digital versatile disk) and/or reproducing information recorded on the optical disk, and, more specifically, to an optical pickup in which a linear spring member for movably supporting a lens holder is surrounded by damper gel so as to be capable of actively damping deflection of the linear spring member.
2. Description of the Related Art
Conventionally, the optical pickup for recording on and/or reproducing information from the optical disk such as a DVD includes an objective lens for converging a light beam on the optical disk, a lens holder for holding an objective lens, a magnetic drive mechanism for driving the lens holder in the focusing direction and in the tracking direction, a supporting mechanism movably supporting the lens holder and functioning as a suspension for the lens holder, and a chassis for mounting a light-emitting element, a light-receiving element, and various optical components.
The magnetic drive mechanism includes a focus coil and a tracking coil mounted on the lens holder and a magnetic circuit, and the focus coil and the tracking coil are arranged so as to provide transverse magnetic flux from the magnetic circuit.
The supporting mechanism includes a plurality of linear springs fixed at one end to the lens holder, a supporting member functioning as a leaf spring that bends in the direction of the length of the linear spring and supporting the linear spring at the other end, a damper gel formed of gelatinous material surrounding the linear spring for actively damping deflection mainly in the direction of focus, that is, pitching, and a holding member provided between the lens holder and the supporting member, with the holding member including holes through which the plurality of linear springs are inserted, and the damper gel being held in the holes. There is provided a gap between the holding member for holding the damper gel and the linear springs, and the gap is entirely filled with the damper gel.
In the optical pickup thus constructed, information is recorded/reproduced by irradiating a light beam converged through the objective lens on a data track on the optical disk. In this case, focus servo control that controls a spot of light beam to be focused on the data track, and tracking servo control that controls the spot of light beam to follow the data track are performed.
In other words, when the optical pickup is under focus servo control, a current flows through the focus coil to generate an electromagnetic force in the direction of the optical axis of the objective lens and the lens holder is driven in the direction of the optical axis of the objective lens, so that the spot of the light beam is exactly focused on the data track. On the other hand, when the optical pickup is under tracking servo control, a current flows through the tracking coil to generate an electromagnetic force in the direction orthogonal to the optical axis of the light beam, and the lens holder is driven in the direction orthogonal to the optical axis of the objective lens, so that the spot follows the data track.
When the lens holder is being driven in this manner, the linear spring and the supporting member function as suspensions respectively for deflections of the lens holder in the direction of focus and for deflection of the same in the direction of tracking. In this case, deflection in the direction of focus, deflection in the direction of tracking, and rotation about the radial axis (in the direction of the radius of the optical disk) or pitching of the linear spring itself are actively damped by the damper gel.
The optical pickup of this type tends to be thinner, and thus the distance between the holding member for holding the damper gel and the optical disk is set to a small value. Therefore, in the conventional optical pickup described above, when a cleaner having projections such as a brush or the like is used on the optical disk for wiping off dirt attached to the optical lens, the projections of the cleaner come into contact with the damper gel filling the gap between the holding member for holding the damper gel and the supporting member for supporting the linear spring, which may result in the damper gel being inadvertently attached to the objective lens.